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Women Who Smoke Have Increased Risks of Colorectal Cancer: Presented at ACG

By Paula Moyer

HONOLULU, HI -- November 9, 2005 -- Women who have a history of tobacco use have a higher risk of acquiring colorectal cancer, according to investigators who presented findings here at the 70^th annual meeting of the American College of Gastroenterology (ACG).

"We can see that while both men and women who use tobacco and alcohol are diagnosed with colorectal cancer at an earlier age, the effect of tobacco is significantly greater in women," said principal investigator Anna L. Zisman, MD, in her presentation on November 1^st.

"Understanding the interactions between [risk factors] is critical for colorectal cancer risk stratification and will help us design effective screening strategies," said Dr. Zisman, who is Research Physician in Internal Medicine, Evanston Northwestern Healthcare, Evanston, Illinois, United States. She received this year's ACG Radhika Srinivasan Gender Based Research Award for this research.

She and her co-investigators conducted the study based on earlier research which showed that women with colorectal cancer tend to have more proximal disease and more microsatellite unstable lesions than men with the disease.

Their study focused on smoking and alcohol use because they are well-known CRC risk factors but with little known about differences in men's and women's vulnerability. They performed a retrospective analysis of the gender-based risks of using tobacco and alcohol, and used the age of onset of colorectal cancer as a surrogate marker.

For the study, the investigators used 1993 to 2004 data from the IMPAC Medical Registry Services Cancer Information Resource file, a database that includes more than 350 hospitals. They analyzed the data by gender, as well as history of tobacco and alcohol use.

In the baseline non-smoking and non-drinking categories, men developed colorectal cancer at an average age of 69.1 years and women at 72.5 years (P < .001). Among current smokers the average age of onset was 66.0 for men and 65.1 for women (P < .001 for both compared to baseline). Among those who consumed alcohol the average age of onset was 67.9 years for men and 64.4 years for women (P < .001 for both compared to baseline).

When the investigators assessed the differential sensitivity to smoking and alcohol use in men and women, they found that women were more sensitive than men to tobacco but not alcohol. Among women who smoked but did not drink, the average age of onset was 6.5 years younger than the baseline group; in men, the age difference was 3.9 years (P < .001). In women who smoked and drank, the age of onset was an average of 9.4 years younger than baseline; men were an average of 6.8 years younger (P < .001). Among nonsmokers who drank, the average age of onset was 4.6 years younger for both men and women.

Therefore, the investigators concluded that, although tobacco and alcohol decrease the age of onset for colorectal cancer for both men and women, the deleterious effect of tobacco is significantly worse for women.


[Presentation title: Gender-specific Promotion of Colorectal Cancer Risk by Tobacco but Not Alcohol Use. Abstract 16]

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